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HRT03 and DS18B20 sensors heating up

Former Member

Hello all,

 

Just wondering if anyone has experienced issues with temperature sensors heating up when connected to the RPi.

 

I purchased one of the HRT03 and DS18B20 temperature sensors today to test some monitoring options using a raspberry pi. I tried the instructions set out on a few sites on the internet for setting these up, however the temperature never displayed using wiringPi (only saw the checksum stats), and now when I plug the devices in, if they don't shut my RPi down, they get incredibly hot to the touch.

Have I burned these out accidentally, or is there something else I should try?

For the RHT03 (exposed side facing me, pin count left to right), pin 1 was going to 3.3v on the RPi, pin 2 went to one several GPIO data ports, and pin 4 went to Ground.

For the DS18 (flat side facing me, pin count left to right), pin 1 went to ground, pin 2 to GPIO port, and pin 3 to 3.3v and to 5v.

 

I did see some diagrams outlining a need for a 4.7k or 10k resistor between pin 3 and pin 2, but that didn't seem to make any difference to reporting using the wiringPi utility.

 

Any thoughts or input from the community?

 

Thanks

  • Hi Ryan, What is an HRT03? The DS18B20 is a maxim 1-wire temperature sensor that can take power from a tr-state or open drain pin. It needs a pull up resistor. If very hot to touch (can you keep your finger on the device?) it sounds like damage.


    Peter

  • First of all, have you read the data sheets for both of these? To understand how they work and important other things. Here is a very good explanation how Max works http://pdfserv.maximintegrated.com/en/an/AN4679.pdf.

    Overtemperature Outputs

    Most digital temperature sensors include one or more outputs that

    indicate that the measured temperature has gone beyond a preset (usually software-

    programmable) limit. The output may behave like a comparator output, with one state when

    temperature is above the threshold and the other state when temperature is below the

    threshold. Another common implementation is for the output to behave as an interrupt that is

    reset only in response to an action by the master.

    Did you program this? That can be the problem here! BTW, this sensor is a digital sensor with certain constraints like how many times it samples! Too many and it may overheat.

    Clem